Resistance unit and rheostat



H. G. RICHTER RESISTANCE UNIT AND RHEOSTAT Filed Jan. 28, 1927 2 Sheets-Sheet 1 f 6' I Era-6"- 55 IN VEN TOR. fi ezzzg fzz'ci A TTORNE July 10, 1928. 1,676,869 H. G. RICHTER RESISTANCE UNIT AND RHEOSTAT Filed Jan. 28, 1927 I z Sheets-Sheet 2 IN VEN TOR.

M Pm? meme July 10,1928.

UNITE]? STATES PATENT OFFICE.

HENRY G. RICHTER, OI ROSELLE PARK, NEW JERSEY, ASSIGNOR TO ELECTRAD, INQ, OI NEW YORK, N. Y., A CORPORATION OF NEW YORK.

RESISTANCE UNIT ANIJ RHEOSTAT.

Application filed January 28, 1827. Serial No. 184,238.

My invention relates broadly to electrical resistance units and more articularly to a compact construction of e ectrical resistor which may ;be manufactured and assembled inexpensively on a quantity production basis.

One of the objects of my invention is to provide an electrical resistor having a minimum number of parts capable of bein mounted within a small physical space an yet provide-for a relatively high reslstance.

Another object of my invention 1s to provide a resistance unit formed upon a screw threaded base member upon opposite ends of which I provide screw threaded cap members for forming terminals for the opposite ends of the resistance unit which is constituted by a wire spirally wound upon the screw threaded body portion with the ends grlpped by the cap members forming the electrical terminals.

My invention will be more fully understood from the specification hereinafter following by reference to the accompanying drawings wherein:

Figure 1 illustrates the resistance member; Fig. 2 shows the insulated screw threaded supporting body which carries the resistance, illustrating the body portion in side and end elevation; Fig. 3 showsan assembly cross-sectional view ofthe reslstance unit; 'Fig. 4 is an assembly view with parts of the screw threaded caps broken away to show the method of connection between the caps and the resistance member; Fig. 5 illustrates one of the applications of the resistance unit of my invention arranged to have its value readily controlled; Fig. 6 shows a modified form of the resistance unitof my invention with means for varyin the effective value of different sections 0 the unit; and Fig. 7 is a wiring diagram showing the electrical circuit through the re sistance units of my invention.

The resistance unit of my invention has been designed with a view of providing a number of mechanical and electrical advantages over constructions of resistors heretofore available in the art. Among the mechanical advantages of the resistance unit of my invention I may mention its ease of manufacture, the stability and sturdiness of the completed unit, and the ease of adaptability of the resistor to fixed or variable combinations of the electrical circuits. Among the electrical advantages possessed by the resistor of my invention I may mention the the metal core 1, and over this insulated e'n-' 'velope or tube I wind a resistance wire 3 with its convolutions spaced one from another.

A heat resisting body structure which is machined or molded from insulating material is represented in Fig. 2 as consisting of a cylindrical body having V-shaped threads cut or .molded therein. The body portion 4 may be tubular in shape with a longitudinal bore 27 extending therethrough and slots 5 and 6 at opposite ends of the member 4: and in one side of the body portion. In the V- shaped threads the resistance element is spirally wound as represented at 3, the wire member being freely exposed to air; The .opposite ends of the member 4 are-provided with screw threaded caps 7 and 8 which abut with the free ends of the resistance wire 3 which are bent over and interlocked in the threads as represented in Figs. 3 and 4. The same screw threads 4 which provide supports and separators for the resistance wire 3, also provide means for supporting the terminal cap members 7 and 8: In special cases, how ever, it may be advantageous to use a diiferent thread gauge for the caps.

In Fig. 5 I have illustrated the adaptability of the resistor of my invention to a mounting in which the effective value 'of the resistance may be controlled. The mounting is shown consisting of a base member 11 carrying a journal 12 for a switch member 14. Suitable supports, such as resilient clip members 9 and 10 are carried by the base 11 and the resistor may be slipped into the clips with the terminal caps 7 and 8 thereof engaging the clips. Inasmuch as the resistance wire 3 is non-insulated and freely exposed to the air, the switch arm 14 may sweep over and contact with the convolutions of the resistance wire 3 in a path which I have represented at 15. a

In adapting the resistance element to various types of apparatusit becomes desirable at timesto provide for the variation '0f the effective resistance over a plurality of sections of the resistance. I have shown a plurality of fixed sections 20,- 21 and 22,

and a plurality ofsections 23 and 25, the efiective value of resistance in which may be varied, as represented by variable contact 7 members- 24 and 26.

tion comprises a; minimum number of parts.

a This facilitates manufacture and.'produc tion and considerably reduces manufactur ing costs. The resistance element is supported in position upon the screw threaded member by bending theends oi the element into slots and 6 and .then electrical connections established by the metallic caps 7; and 8 with the resistance wire. 'By reason of the complete exposure of the resistance 7 wire to the air and the fact that no insular,

and that no limitations upon the'ii'nvention tion is provided on the wire, higher efliciency may be obtained and greater electrical power can be dissip'ated.'.

It will be understood that while I have described my invention in certain preferred embodiments, that modifications may be made by Letters Patentof the United States is member comprising a metallic core, aninsulated envelopethereon, and a resistance wire spirally wound thereover, saidresistance member beiIi wound in the screw threads of said cylin rical member and terminating envelope of insulating material wound over said metallic core, and a resistance wire spirally Wound over said heat-resisting insulation material, said resistance element being spirally wound in the screw threads of said insulated cylindrical body, terminals on opposite ends of said body structure for gripping the ends of said resistance wire and establishing connection between opposite ends thereofand said terminals.

3. A variable resistor comprising a screw threaded body member of insulated mate- From the foregoing explanation it willrial, an insulated member having afspi'rally be understood that theresi'stor of my invenwound resistance wire thereon, said insulated member and resistance wire beingwound in said screw threads, metallic cap members engaging the ends of said screw threaded bo y member and connected with the opposite ends of said resistance wire, and a slidable contact member arranged to engage with the corivolutions of said spirally wound resistance wire for effectively including a predetermined amount of said resistance in an external circuit.

4:. A varlable reslstor comprising a screw threaded body member of insulated material,"an insulated member having a'spirally wound resistance wire" thereon, said insulated member and reslstancewire being wound vin said screw threads, metalliccap-members engaging the ends of said screw threaded be. y

member and connected with the opse ue ends of said-resistance wire, said resistance wire being divided into a lurality of sections with independently a justablemeans for slidably engaging selected ortions of said sections forefl'ectively inc ud-' ing predetermined amounts of sad resistance in external circuits. 1

- HENRY G. RICHTER. 

